From a536c5d33cdb7142170112088b48cf22d4c76714 Mon Sep 17 00:00:00 2001
From: rjl493456442 <garyrong0905@gmail.com>
Date: Tue, 23 Jul 2019 14:06:41 +0800
Subject: [PATCH] core: skip tx indices writing during fast sync

---
 core/blockchain.go                 | 24 ++++++++++++++++++------
 core/rawdb/accessors_chain_test.go | 30 +++++++++++++++++-------------
 2 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/core/blockchain.go b/core/blockchain.go
index dbd472ea07..aa04593ff2 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1090,7 +1090,11 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 			}
 			// Flush data into ancient database.
 			size += rawdb.WriteAncientBlock(bc.db, block, receiptChain[i], bc.GetTd(block.Hash(), block.NumberU64()))
-			rawdb.WriteTxLookupEntries(batch, block)
+
+			// We don't write tx lookup indices here because Geth can offer a CLI flag `txlookuplimt`
+			// with which user can choose to drop historical indices data and only keep latest indices.
+			// After the fast sync, we will reconstruct all missing indices even user requires to keep
+			// all historical indices.
 
 			stats.processed++
 		}
@@ -1165,7 +1169,11 @@ func (bc *BlockChain) InsertReceiptChain(blockChain types.Blocks, receiptChain [
 			// Write all the data out into the database
 			rawdb.WriteBody(batch, block.Hash(), block.NumberU64(), block.Body())
 			rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), receiptChain[i])
-			rawdb.WriteTxLookupEntries(batch, block)
+
+			// We don't write tx lookup indices here because Geth can offer a CLI flag `txlookuplimt`
+			// with which user can choose to drop historical indices data and only keep latest indices.
+			// After the fast sync, we will reconstruct all missing indices even user requires to keep
+			// all historical indices.
 
 			stats.processed++
 			if batch.ValueSize() >= ethdb.IdealBatchSize {
@@ -2080,10 +2088,14 @@ func (bc *BlockChain) updateTxIndices() {
 			rawdb.IndexTxLookup(bc.db, from, to) // No block has been indexed.
 		} else {
 			rawdb.IndexTxLookup(bc.db, from, *oldest)
-		}
-		// Delete useless tx indices if user requires.
-		if from > 0 {
-			rawdb.RemoveTxsLookup(bc.db, 0, from)
+
+			// Drop all useless tx indices below the HEAD-limit.
+			if from > 0 {
+				oldest := rawdb.FindOldestIndexedBlock(bc.db, 0, from)
+				if oldest != nil {
+					rawdb.RemoveTxsLookup(bc.db, *oldest, from)
+				}
+			}
 		}
 		log.Debug("Initialised transaction indices", "elapsed", common.PrettyDuration(time.Since(start)))
 	}
diff --git a/core/rawdb/accessors_chain_test.go b/core/rawdb/accessors_chain_test.go
index aacbe32216..810a948dac 100644
--- a/core/rawdb/accessors_chain_test.go
+++ b/core/rawdb/accessors_chain_test.go
@@ -361,20 +361,24 @@ func checkReceiptsRLP(have, want types.Receipts) error {
 
 func TestFindOldestIndexedBlock(t *testing.T) {
 	var cases = []struct {
-		empty     bool
 		oldest    uint64
 		height    uint64
 		nilBlocks map[uint64]bool
+		start     uint64
+		end       uint64
 		expect    uint64
+		expectNil bool
 	}{
-		{true, 0, 10, nil, 0},  // No block has been indexed
-		{false, 0, 10, nil, 1}, // Genesis block doesn't have indices
-		{false, 1, 10, nil, 1},
-		{false, 4, 10, nil, 4},
-		{false, 5, 10, nil, 5},
-		{false, 6, 10, nil, 6},
-		{false, 10, 10, nil, 10},
-		{false, 3, 10, map[uint64]bool{4: true, 6: true, 8: true}, 5},
+		{11, 10, nil, 0, 10, 0, true}, // No block has been indexed
+		{0, 10, nil, 0, 10, 1, false}, // Genesis block doesn't have indices
+		{1, 10, nil, 0, 10, 1, false},
+		{5, 10, nil, 0, 10, 5, false},
+		{5, 10, nil, 0, 5, 5, false},
+		{5, 10, nil, 0, 4, 0, true},
+		{5, 10, nil, 5, 5, 5, false},
+		{5, 10, nil, 10, 10, 10, false},
+		{10, 10, nil, 0, 10, 10, false},
+		{3, 10, map[uint64]bool{4: true, 6: true, 8: true}, 0, 10, 5, false},
 	}
 	for cid, c := range cases {
 		var (
@@ -394,15 +398,15 @@ func TestFindOldestIndexedBlock(t *testing.T) {
 			}
 			WriteBlock(db, block)
 			WriteCanonicalHash(db, block.Hash(), block.NumberU64())
-			if !c.empty && block.NumberU64() >= c.oldest {
+			if block.NumberU64() >= c.oldest {
 				WriteTxLookupEntries(db, block)
 			}
 		}
-		res := FindOldestIndexedBlock(db, 0, c.height)
-		if c.empty && res != nil {
+		res := FindOldestIndexedBlock(db, c.start, c.end)
+		if c.expectNil && res != nil {
 			t.Fatalf("Case %d failed, oldest block mismatch, want nil, have %d", cid, *res)
 		}
-		if !c.empty && *res != c.expect {
+		if !c.expectNil && *res != c.expect {
 			t.Fatalf("Case %d failed, oldest block mismatch, want %d, have %d", cid, c.expect, *res)
 		}
 	}